EUVD-2026-68688Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Exploitation requires a valid bearer key (PR:L) and group routing enabled; no scope change occurs and availability is unaffected by authorization bypass alone.
Primary rating from Vendor (github).
CVSS VectorVendor: github
Lifecycle Timeline
5DescriptionCVE.org
MCPHub is a unified hub for centrally managing and dynamically orchestrating multiple MCP servers/APIs into separate endpoints with flexible routing strategies. Prior to version 1.0.31, when a bearer key with accessType: 'servers' (or 'custom') is used against a group route, isBearerKeyAllowedForRequest grants access to the entire group as long as any single server in that group appears in the key's allowedServers list - not only when every server the key is scoped to matches, and critically, without ever re-checking allowedServers again once the group-level connection is authorized. A key explicitly scoped to one specific server therefore also grants full access to every other server that happens to share a group with it, including servers the key was never authorized for. This issue has been patched in version 1.0.31.
AnalysisAI
Bearer key scope escalation in MCPHub prior to version 1.0.31 allows an authenticated API client holding a server-scoped key to silently access every server within a group, not just the one explicitly authorized. The isBearerKeyAllowedForRequest function performs an any-overlap check at the group level - if any server in the key's allowedServers list belongs to the requested group, the entire group is unlocked for that session with no further per-server re-validation. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires possession of a valid bearer key with accessType set to 'servers' or 'custom', with at least one server listed in its allowedServers. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 8.1 score (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N) accurately reflects the attack profile: network-reachable, low complexity, requiring only a valid but limited-scope bearer key with no user interaction. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Upgrade MCPHub to version 1.0.31 or later, available at https://github.com/samanhappy/mcphub/releases/tag/v1.0.31. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory all MCPHub deployments, identify current versions (especially those prior to 1.0.31), and catalog all active bearer keys and their assigned scopes. …
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Same weakness CWE-863 – Incorrect Authorization
View allSame technique Authentication Bypass
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External POC / Exploit Code
Leaving vuln.today